Genetic architecture of kernel composition in global sorghum germplasm

Abstract

BackgroundSorghum [Sorghum bicolor (L.) Moench] is an important cereal crop for dryland areas in the United States and for small-holder farmers in Africa. Natural variation of sorghum grain composition (protein, fat, and starch) between accessions can be used for crop improvement, but the genetic controls are still unresolved. The goals of this study were to quantify natural variation of sorghum grain composition and to identify single-nucleotide polymorphisms (SNPs) associated with variation in grain composition concentrations.ResultsIn this study, we quantified protein, fat, and starch in a global sorghum diversity panel using near-infrared spectroscopy (NIRS). Protein content ranged from 8.1 to 18.8%, fat content ranged from 1.0 to 4.3%, and starch content ranged from 61.7 to 71.1%. Durra and bicolor-durra sorghum from Ethiopia and India had the highest protein and fat and the lowest starch content, while kafir sorghum from USA, India, and South Africa had the lowest protein and the highest starch content. Genome-wide association studies (GWAS) identified quantitative trait loci (QTL) for sorghum protein, fat, and starch. Previously published RNAseq data was used to identify candidate genes within a GWAS QTL region. A putative alpha-amylase 3 gene, which has previously been shown to be associated with grain composition traits, was identified as a strong candidate for protein and fat variation.ConclusionsWe identified promising sources of genetic material for manipulation of grain composition traits, and several loci and candidate genes that may control sorghum grain composition. This survey of grain composition in sorghum germplasm and identification of protein, fat, and starch QTL contributes to our understanding of the genetic basis of natural variation in sorghum grain nutritional traits.Electronic supplementary materialThe online version of this article (doi:10.1186/s12864-016-3403-x) contains supplementary material, which is available to authorized users.

Characterization of Local Sorghum (Sorghum bicolor L.) Population Grains in Terms of Nutritional Properties and Evaluation by GT Biplot Approach

“…and Zhang et al . The starch content of the samples in the current study was found to be similar to the results of some researches …”

Genetic Basis of Protein Digestibility in Grain Sorghum

“…This range is wide, and cultivars with a protein content of 16% or higher could be considered high protein compared with the average protein content for the crop, which is ?11%. The development of high-throughput near-infrared reflectance spectroscopy for rapid measurement of sorghum seed compositional traits is an important technological advancement that could be exploited for use in breeding programs targeting increased protein level in sorghum (Hicks et al, 2002, Sukumaran et al, 2012Rhodes et al, 2017). Given the diversity for the trait, its high heritability, and its consistent expression across environments (Badigannavar et al, 2016;Rhodes et al, 2017), efforts to breed high-protein cultivars should lead to reasonable success.…”

“…Sorghum, particularly durra and dura-bicolor races, is high in protein content compared with other cereal grains (Johnson et al, 1968;Rhodes et al, 2017). Sorghum, particularly durra and dura-bicolor races, is high in protein content compared with other cereal grains (Johnson et al, 1968;Rhodes et al, 2017).…”

“…Half or more of the protein in a mature cereal grain may be storage protein. Grain sorghum protein content ranges from 6 to 18% (Subramanian et al, 1990;Vendemiatti et al, 2008;Rhodes et al, 2017), but there are some sorghum germplasm lines with exceptionally high protein content of up to 25% ( Johnson et al, 1968). Based on solubility, sorghum grain proteins are grouped into albumins (water extractable fraction), globulins (dilute salt extractable fraction), prolamins (aqueous alcohol extractable fraction), and glutelins (alkali soluble fraction) (Osborne, 1924).…”

Genome‐Wide Association Mapping of Grain Mold Resistance in the US Sorghum Association Panel

“…Today, the SAP is an important germplasm source used for the study of multiple economic important traits. Genome‐wide association studies (GWAS) using these resources have resulted in the discovery of multiple SNP–trait associations that provide insight into its genetic architecture (Adeyanju et al, 2015; Boyles et al, 2016; Chen et al, 2017; Cuevas et al, 2018a; Hayes et al, 2015; Morris et al, 2013b; Rhodes et al, 2014, 2017),…”